The invention relates to a method of and an apparatus for high intensity heat and/or mass transfer between two or more phases, wherein the contacting phases are caused to form an intensive stream along a helical path in a space determined by suitable elements.
Arrangements for two phase contact are made for different materials frequently used in chemical technology and in related technical branches. In the process three phases often take part in the process simultaneously, as for instance absorption, desorption, rectification, drying, cooling or heating of granular or powder material, adsorption, chemosorption, catalytic processes in connection with supply or removal of heat and the like. Research and practice are endeavoring to find new ways of intensification of similar processes. In such research there is encountered the problem of limited driving power for the movement of the phase with the higher specific mass, the magnitude of which, of course, is determined by the intensity of the gravitational field of the earth.
This circumstance causes, in the case of a countercurrent contact of the phases, which is characterized by a higher final concentration or temperatures respectively, and a larger driving force of the processes, and increasing entrainment of the phase with a higher specific mass, such loss being proportional to the increasing speed of the phase with the lower specific mass. When a critical speed is reached, the apparatus becomes flooded, or an inverse streaming is caused, whereby the functioning of the whole arrangement as a countercurrent arrangement is affected. A solution to this problem by the creation of an arrangement of the cocurrent - countercurrent type did not have the expected effect, and in its practical realization a number of difficulties particularly in design were met, not to mention a decrease of the driving force in the case of a contact of phases as above-arranged.
An apparatus is already known wherein the transfer of heat or mass between a gaseous or vapor phase on the one hand and of a liquid phase on the other hand is accomplished on the internal wall of a cylindrical surface, whereby the liquid phase enters tangentially into the upper part of the arrangement and forms a rotating film on the wall of the cylinder, with the gaseous or vapor phase moving in counter-current and similarly receiving a rotating movement. When comparing the achieved mass transfer coefficients with values published in technical papers (Chem. Eng. Progr. Vol. 45, 11, 677 -- 1949 Koch a. o.); this arrangement showed an intensity calculated at eight to fifteen times higher with respect to a unit of the dry surface of the packing as used according to this paper. But despite that, the above-mentioned arrangement has the drawback in that when using arrangements of larger height, the liquid phase at an inlet speed of any available height forms only about one and one-half turns and subsequently flows down due to gravitational forces practically vertically without forming a spiral track. The speed of the phase with the lower specific mass remains practically at several meters per second. It is therefore obvious that the negative influence of the reduction of the centrifugal acceleration with respect to the gravitational acceleration has prevailed, thereby determining the character of flow of the liquid phase in the middle part of the column. It has been found that a complicated rear flow takes place which compensates the concentration and thus reduces the driving forces of the process.